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In May, levels of carbon dioxide in the Earth's atmosphere surpass 400 parts per million for the first time in human history. Photo: Reuters

It's been another year of discovery and innovation. Here, courtesy of the Australian Science Media Centre, are the 10 most momentous moments in science this year - and the 10 strangest.

THE TOP 10

Space sounds revealed Voyager 1 had boldly gone

In September, NASA's Voyager 1 spacecraft became the first man-made object to leave our solar system and venture into interstellar space. The probe, launched in 1977 with the aim of reaching Jupiter and Saturn, is now more than 19 billion kilometres from the sun. Scientists listened in to vibrations in the plasma surrounding Voyager – the sound of interstellar space - after it was hit by a massive solar wave in April. The vibrations allowed them to calculate the plasma's density, which differs between our solar system and interstellar space, confirming Voyager was no longer in our solar system.

Carbon dioxide hit a new peak

In May, levels of carbon dioxide in the Earth's atmosphere reached a symbolic milestone, passing 400ppm (parts per million) for the first time in human history. Just a few months later in September, the leading international body for the assessment of climate change, the Intergovernmental Panel on Climate Change (IPCC), found that human influence on the climate system is clearer than ever - we are now 95 per cent certain that humans are the cause of global warming. Climate scientists from the CSIRO and the Bureau of Meteorology were among the more than 600 scientists and researchers who worked on the IPCC report.

Scientists created cloned human stem cells

In May, researchers used therapeutic cloning to create human embryonic stem cells for the first time. The process involved taking the nucleus - which contains the genetic material - from a normal cell and transferring it into an unfertilised egg with its own genetic material removed. While this approach had previously been used in monkeys and mice, it had never succeeded using human cells. This discovery, described by Australian scientists as "a major breakthrough in regenerative medicine", could help develop personalised therapies for a range of currently untreatable diseases. However, the process requires human donor eggs, which are not easy to obtain, and raises a number of ethical issues.

The world's most expensive burger was grown in the lab

The world's first lab-grown burger was cooked and eaten at a news conference in London in August this year – generating headlines around the world.  The burger patty – which one food critic described as 'close to meat' - was developed by scientists from Maastricht University in the Netherlands through research funded by Google co-founder Sergey Brin. Starting with stem cells from a biopsy of two cows (a Belgian blue and a blonde d'Aquitaine), the scientists grew muscle fibres in the lab. The fibres were pressed together with breadcrumbs and binding ingredients, then coloured with beetroot juice and saffron, resulting in the most expensive hamburger in history at a cost of around AU$367,000.

Doctors stopped HIV in its tracks

A child born with HIV and treated with a series of antiviral drugs for the first 18 months of its life was found to be free of the virus more than 12 months after treatment ended. When the infant was 30 months of age, HIV-1 antibodies remained completely undetectable. However, the big question of whether this child, known as the "Mississippi baby", has truly been cured of HIV remains unanswered. "The best answer at the moment is a definitive maybe", HIV expert Scott Hammer, wrote in a New England Journal of Medicine editorial which accompanied the research.

The oldest signs of life were found in WA

Scientists working in the Pilbara found what they believe to be the oldest fossils ever discovered - created by a mat of microbes that lived 3.5 billion years ago. The minuscule remains were found inside a lump of sandstone by scientists from OId Dominium University in the US and are thought to be 300 million years older than similar fossils and one of the most ancient signs of life on Earth.

A king turned up in a car park

In February the bones of Richard III were discovered in the inauspicious surroundings of a car park in Leicester, England - more than 500 years after he died. Radiocarbon dating, radiological evidence, DNA and bone analysis all helped confirm the identity of last Plantagenet king. As if the indignity of being dug up in a car park wasn't bad enough, further research revealed Richard was infected with roundworms in his intestines. In a similar tale closer to home, 50 million-year-old fossils of crocodiles, frogs, fish and plants were found by a work crew drilling a hole for a bridge support at a construction site in Geebung in Brisbane in July.

An Aussie frog was resurrected

Australian scientists announced in March that they had succeeded in growing early stage embryos containing the DNA of an extinct frog. The research is the first step of Project Lazarus, which aims to bring the Australian gastric-brooding frog back to life. The scientists took nuclei - which contain the extinct frog's DNA - from frozen tissue samples collected in the 1970s. The nuclei were injected into donor eggs from a distantly-related frog. Some of the eggs went on to divide and grow into embryos, reviving hopes for an animal that has been extinct since 1983. The research was listed as one of Time magazine's top 25 inventions of this year

Australian scientists helped design a new flu drug

Researchers from CSIRO announced in February that they had helped to design a new flu drug with the potential to prevent the spread of different strains of the virus, including drug resistant strains.  In order to infect cells, flu binds to sugars on the surface of our cells and it has to remove these sugars to be able to spread. The new drug works by preventing the virus from removing the sugars, stopping it from infecting additional cells and causing full-blown illness.

The world's largest volcano was discovered

In September, scientists discovered the largest single volcano on Earth under the Pacific Ocean. The mega-volcano spans 650 kilometres - similar to the distance between Melbourne and Canberra - but don't worry, it's been slumbering for the last 145 million years. Scientists had thought the volcano, known as Tamu Massif,  was a series of volcanoes, but the Integrated Ocean Drilling Program - of which Australia is a partner - showed that it is in fact a single, immense volcano, constructed from massive lava flows that emanated from the volcanic centre to form a broad, shield-like shape.

THE 10 WEIRDEST

We can smell 10 smells – and one of them is popcorn!

We all know tastes can be classified into five distinct flavours, but research released in September suggested there are 10 basic categories of odour – and that one of them is popcorn. The other odours are fragrant, woody/resinous, fruity (non-citrus), chemical, minty/peppermint, sweet, lemon and two kinds of sickening odours: pungent and decayed.

Farts on a plane are 'better out than in'

Talking of pungent and decayed, in February a team of Danish and British gastroenterologists discussed that while holding back a fart on an aeroplane may cause significant discomfort and physical symptoms, releasing flatus presents social complications, leaving potential aerial farters in a quandary. Suggesting that there's truth in the tradition of 'better out than in', the researchers also provide advice on how to get away with it. They recommend walking up and down the aisle if you want to let rip as "the social problems of flatulence are reduced, since the odour is distributed over a larger area". And the final take home message? "The future frequent flyer may develop the ability to "sneak a fart" by wearing charcoal-lined underwear thus experiencing a comfortable flight in harmony with fellow passengers." We can only hope.

Sorry boys, size matters after all

In April, Australian researchers showed that, when it comes to attractiveness at least, penis size does matter. Using a series of life-sized, computer-generated images of male figures, they discovered that women rated the 'cyber' men as more attractive as penis size increased. But there is some comfort for less well-endowed blokes out there, assuming you're also tall - increased height had an almost equivalent positive effect. The results suggest the female tendency to choose a man with a bigger manhood could have driven the evolution of larger penises in humans.

Applause is infectious

Scientists found that when it comes to applause, it's not the quality of performance, but peer pressure that affects clapping. In June, researchers revealed that clapping spreads through a crowd like an infection, and that it's the social pressure from people around us who start or stop clapping that has the biggest influence on how long we applaud. It seems no-one likes to be the first or the last caught clapping.

Insects hitched a ride on robots

Forget dogs driving cars, in February moths got their own mode of transport - robots. Japanese researchers developed a two-wheeled robot that's driven by a male silk moth. The moths steer the machine towards enticing female sex pheromones, allowing researchers to monitor their neural activity.

Detachable penises and an inevitable headache

It might have seemed ridiculous in the mildly popular '90s song, but in February scientists were surprised to discover a sea slug with a truly detachable penis. The sea slug, Chromodoris reticulata is able to dispose of its penis after sex and grow a new one within 24 hours - a feat it can repeat at least three times. And in similarly weird sea slug sex news, in November, Australian scientists found that a Great Barrier Reef species stabs its sexual partners through the head during mating. The researchers suggest this 'head injection' shoots prostate gland secretions into the recipient's central nervous system, directly affecting their physiology.

Scientists figured out how to read our dreams

We've all been bored rigid by other people recounting their dreams, but in April Japanese researchers read people's dreams directly for the first time. The scientists first built up a database of dream images by scanning peoples brains using magnetic resonance imaging (MRI) while they slept, then waking them and asking them to describe the images in their dreams. By matching the images to the brain maps, they were then able to predict which images people had dreamt about just by looking at the brain scans, getting it right about two thirds of the time.

Szechuan peppers pack a punch

If you think eating a Szechuan pepper feels a bit like a slap in the mouth, you're right. In September, UK scientists showed that the signal sent to the brain in response to eating a spicy Szechuan peppercorn is the equivalent of 50 light taps on the skin every second, mimicking the sense of touch.

Illusory fake fingers fooled our brains

In September, Australian researchers revealed a whole new class of illusion by tricking the brain into believing a fake finger was the real thing using only sensory inputs from muscles. The illusion shows that the body does not require sight or touch to sense which parts of your body belong to you, or to determine their positions in the world.

Dogs can tell left from right

You might think a wagging tail is a wagging tail, but you could be underestimating man's best friends. Italian research released in November suggested dogs recognise and respond differently when their fellow canines wag to the right than when they wag to the left. The findings show that dogs, like humans, have asymmetrically organised brains, with the left and right sides playing different roles.